Temporal and spatial variation of surface sensitive heat fluxes over the middle and eastern Tibetan Plateau

doi:10.12006/j.issn.1673-1719.2017.058

Abstract

Abstract:

Based on the site data of the Tibetan Plateau (TP) from 1970 to 2015, the sensible heat fluxes over the middle and eastern Tibetan Plateau were calculated by physical method. Moreover, according to the discrimination of average heat transfer coefficients over the middle and eastern TP, utilizing wavelet analysis, correlation analysis, we divided TP whose altitude is more than 3000 m into 7 areas to study the temporal and spatial characteristics of the sensible heat fluxes and impact factors over the TP during 1970?2015. It shows that the annual average and spring as well as summer season, sensible heat fluxes period was 3-4 a, while autumn and winter season 2-3 a. The trend of the sensible heat fluxes was increasing during 1970-1980 and 2001-2015, and decreasing during 1980-2001. The strongest heat center (maximum value of sensible heat fluxes) which include annual average and seasonal average emerged in area E (southern slope). However, the minimum value appears in area A of western TP (except summer). Its distribution was uniform in spring and autumn, and presented conspicuous gradient distribution in summer and in winter. In summer, the gradient direction was from east to west, while it was adverse in winter. Although correlation of annual averaged precipitation and annual averaged sensible heat fluxes was not high, it manifested high correlation in spring, summer and autumn. The seasonal transformation of the sensible heat flux was jointly determined by the variation of the 10 m extreme wind speed along the northward and southward and the ground-air temperature difference.

Key words: Sensible heat fluxes, Period, Impact factor, Correlation

Chao ZHANG, Rong-Xiang TIAN, Hui-Ling MAO, Zhi-Fei ZHANG, Zi-Wei SHEN. Temporal and spatial variation of surface sensitive heat fluxes over the middle and eastern Tibetan Plateau[J]. Climate Change Research, 2018, 14(2): 127-136.

Figures/Tables 9

Fig. 1 Sites distribution of the Tibetan Plateau

Fig. 2 Annual average vegetation coverage on the Tibetan Plateau during 1979-2010 and heat transfer coefficients in subareas

Table 1 The sub-region extreme value of the sensible heat fluxes over the Tibetan Plateau and each season

Fig. 3 Inter-annual variation of sensible heat fluxes over the Tibetan Plateau and sub-region during 1970-2015

Fig. 4 Spatial distribution of sensible heat fluxes over the Tibetan Plateau during 1970-2015

Fig. 5 The significance test of period of the sensible heat fluxes over the Tibetan Plateau

Table 2 Correlation analysis of sensible heat fluxes and its influencing factors from 1980 to 2015 in the Tibetan Plateau

Fig. 6 Spatial distributions of ground-air temperature difference during 1970-2015

Fig. 7 Spatial distributions of 10 m wind during 1970-2015

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